Question

x^2-1-2a-a^2 factorise this

Answer 1

x^2-a^2-2a-1
x^2-(a^2+2a+1)
x^2-(a+1)^2
(x-(a+1))(x+(a+1))
x= a+1 or -(a+1)

Answer 2

${x}^{2} - ( {a}^{2} + 2a + 1) \\ {x}^{2} - {(a + 1)}^{2} \\ use \: property \: {a}^{2} - {b}^{2} = (a + b)(a - b) \\ = > (x - (a + 1))(x + (a + 1)) \\ = > (x - a - 1)(x + a + 1)$